This invention generally relates to an inlet valve assembly for controlling the flow of fluid into a chamber, particularly a pumping chamber of a paint sprayer, which allows for accurate adjustment of valve travel in order to minimize the back flow through the inlet valve.
One common type of paint sprayer utilizes a diaphragm pump to draw paint or other fluid through an inlet valve into the pumping chamber and deliver same under pressure through an outlet valve to a sprayer gun or the like. In order to obtain optimum volumetric efficiency in such a pump, the back flow through the inlet and outlet valves must be minimized.
The present invention is concerned with minimizing back flow through the inlet valve, which must be free to open by the vacuum generated by the diaphragm movement on the inlet stroke and be slammed shut at the start of the pressure stroke.
Heretofore, the back flow through the inlet valve was minimized by providing a fixed stop to limit valve travel. However, accurate location of the fixed stop was made difficult because of tolerance problems and the like. Also, the use of such a fixed stop to limit valve travel had the further objection that the amount of inlet valve travel could not readily be adjusted in order to obtain the desired pump flow for different types of paints and other fluids to be pumped.